Combined device comprising a venous blood reservoir and a cardiotomy reservoir in an extracorporeal circuit

ABSTRACT

A combined device having a reservoir for venous blood and a reservoir for cardiotomy blood is disclosed. The device is characterized in that the venous reservoir is separated from the cardiotomy reservoir by a partition which includes a plurality of apertures. The apertures are in fluid communication with a plurality of ducts and passageways which are configured to provide various modes of operation depending upon whether, for the particular surgical conditions, it is desired to mix venous and cardiotomy blood, or to isolate those blood pools from each other.

This is a continuation of application Ser. No. 08/888,777, filed Jul. 7,1997, now U.S. Pat. No. 6,287,270 B1, the contents of which are herebyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention is in the field of devices for use in surgicalprocedures. More particularly, the present invention relates to a devicehaving both a venous blood reservoir and a cardiotomy reservoir for usein an extracorporeal circuit.

BACKGROUND OF THE INVENTION

Many surgical operations involve circulating the blood of a patientthrough an extracorporeal circuit. In particular, many open-heartsurgical procedures require that the patient's heart be stopped, andthat various biological functions (i.e., blood circulation andoxygenation) be performed mechanically by various devices included inthe extracorporeal circuit. In addition to a pump and to the tubingthrough which the blood will flow, devices including oxygenators, heatexchangers, and blood accumulation reservoirs may be employed. Each ofthese devices is monitored and managed by persons who may be present inthe operating room, or at remote monitoring and control stations.

One type of blood accumulation reservoir used in such procedures is avenous reservoir. The venous reservoir serves as a receptacle for blood,typically blood that has been removed from the patient through a vein,which is subsequently oxygenated and further processed prior to beingrecirculated back to the patient. Thus, the venous reservoir typicallyserves to collect blood as it first enters the extracorporeal circuit.The use of the venous reservoir enables the operator to control theblood flow rate, blood pressure, blood volume and related parametersnecessary to maintaining the patient during the surgical procedure.

A second type of blood accumulation reservoir used in such procedures isa cardiotomy reservoir. The cardiotomy reservoir is used to containblood which has been collected from the operating field. Blood collectedin the cardiotomy reservoir can be reinfused into the patient afterbeing filtered to remove any clots or other unwanted contaminants.

Since the space in the operating room available to operators is oftenlimited, devices have been proposed which combine the venous reservoirand the cardiotomy reservoir in a single structure. In such devices,inlets for the venous blood and for the blood from the operating fieldare separated from one another. Blood entering the device is filteredand then collected in a common chamber.

These devices, however, are known to have certain disadvantages. Forexample, the surface area of such devices which comes into contact withthe blood is relatively large. As a result, the blood becomessusceptible to damage or coagulation. Additionally, even underrelatively normal operating conditions, retrograde blood flow may beinduced, causing the blood to be reverse filtered. This is particularlyproblematic if only venous blood is being collected, because theretrograde flow causes the blood to be sequestered within the cardiotomyfilter, thereby reducing the volume of blood available for oxygenationand recirculation to the patient.

OBJECTS AND SUMMARY OF THE INVENTION

One object of the present invention is to provide a combined devicehaving both a venous blood reservoir and a cardiotomy reservoir. Anotherobject of the invention is to provide a device which allows venous bloodand cardiotomy blood to be optionally integrated if surgical conditionsor requirements warrant. Still another object of the invention is toprovide a combined venous blood reservoir and cardiotomy reservoir whichminimize blood contact with large surface areas of the device and whicheliminate the risk of reverse filtration.

These and other objects of the invention are achieved by a combineddevice having a venous blood reservoir and a cardiotomy reservoir. Thedevice is characterized in that it includes a housing having a partitionwhich separates a lower reservoir from an upper reservoir. The lowerreservoir is adapted for use as the venous reservoir, and the upperreservoir is adapted for use as the cardiotomy reservoir. The venousreservoir is provided with a blood inlet connector and a blood outletconnector, and the cardiotomy reservoir and is provided with a bloodinlet connector and with an air outlet connector. Each of the bloodinlet connectors is positioned so that blood entering the device iscaused to flow through a defoaming substance and a filter. Additionally,the partition which separates the venous reservoir from the cardiotomyreservoir is provided with at least two ducts which, starting fromapertures formed in the partition, project upward into the cardiotomyreservoir and reach different elevations therein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of one embodiment of the invention, takenalong a longitudinal plane.

FIG. 2 is an enlarged sectional view, taken along the plane II—II ofFIG. 1.

FIG. 3 is the same sectional view of FIG. 2, but with the device in adifferent operating mode.

FIG. 4 is a sectional view, taken along the plane IV—IV of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the device of the present invention is depicted inFIGS. 1-4.

Regarding FIGS. 2 and 3, and for the sake of clarity, a view of thedevice taken along plane II—II of FIG. 1 is shown. In FIGS. 2 and 3, thecolumn 16 has been rotated 90° into the page with respect to itsposition shown in FIG. 1. With reference to the above Figures, thereference numeral 1 designates a housing of the device and the referencenumeral 2 designates a partition which divides the space enclosed by thehousing 1 into a venous reservoir 3, and a cardiotomy reservoir 4. Thehousing is preferably formed of a transparent polymer to allow theinterior of the device to be viewed by an operator. Numeroustransparent, medically useful polymers are known to those havingordinary skill in the art.

The venous reservoir 3 is provided with an venous inlet connector 5,terminating at 5 a, for the venous blood. Venous blood entering thevenous reservoir 3 through the venous inlet connector 5 enters adistribution chamber 22 where it is passed outward, in a substantiallyuniform manner, into a central region of the venous reservoir through aplurality of slotted apertures 23 formed in the distribution chamber 22.The central region of the venous reservoir is defined by a generallycylindrical wall 6 of a defoaming material. The defoaming material issurrounded by a filter 6 a through which the blood must also pass as itenters the venous reservoir 3. Blood exits the venous reservoir 3through a venous outlet connector 7.

In one embodiment, the defoaming material comprises a porous polymericmaterial such as a polyurethane foam. In one preferred embodiment, thedefoaming material is a polyurethane foam having a pore size ofapproximately 5 to 50 pores per inch, more preferably approximately 20to 30 pores per inch. The defoaming material may optionally be treatedwith a medically acceptable antifoaming agent such as a siliconeantifoaming agent. The filter is a screen, preferably formed of apolyester, having an aperture size in the range of about 20 to 50microns.

The top of the venous reservoir 3 is defined by a partition 2 whichseparates the venous reservoir 3 from the cardiotomy reservoir 4. Thecardiotomy reservoir 4 is provided with a cardiotomy inlet connector 8for receiving blood arriving from the operating field, and an air outletconnector 10. Blood entering the cardiotomy reservoir 4 through thecardiotomy inlet 8 first encounters a flow distributor 24, whichdistributes the blood outwardly in a substantially uniform manner. Aswith the blood entering the venous reservoir, the blood next encountersa generally cylindrical wall 9 of a defoaming material. The defoamingmaterial is surrounded by a filter 9 a through which the blood must alsopass as it enters the cardiotomy reservoir 4. The defoaming material isas described above, namely, a porous polymeric material such as apolyurethane foam. As before, in one preferred embodiment, the defoamingmaterial is a polyurethane foam having a pore size of approximately 5 to50 pores per inch, more preferably approximately 20 to 30 pores perinch, and the filter is a screen, preferably formed of a polyester,having an aperture size in the range of about 20 to 50 microns.

The partition 2 which separates the venous and cardiotomy reservoirs istypically a substantially flat plate. When the device is in operation,it is positioned in a manner that maintains the partition in asubstantially horizontal orientation. The partition 2 is provided with aplurality of apertures that provide for operation of the device in themanner discussed below.

In one embodiment, shown in FIGS. 1-3, the partition 2 includes twoapertures 11 and 12, from which extend two ducts 13 and 14. The ductspreferably extend substantially at right angles to partition 2 andtherefore are maintained in a vertical orientation when the device isoriented in its proper operating position. The ducts 13 and 14 extendinto the cardiotomy reservoir 4 and reach approximately the sameelevation. The upper edge of each duct is typically provided with aplurality of axial notches 15.

An axially moveable column 16 is positioned preferably in the center ofthe cardiotomy reservoir 4 and extends upward through the housing 1. Thecolumn 16 includes a first passageway 17 and a second passageway 18. Inthe first passageway 17, a lower end 17 a communicates with the venousreservoir 3 through a central aperture 20 in the partition 2, and anupper end 17 b communicates with the cardiotomy reservoir 4. Likewise,in the second passageway 18, a lower end 18 a communicates with thecardiotomy reservoir 4 and an upper end 18 b communicates with theexterior of the housing.

Column 16 can be caused to move axially by manual action on tab 19. Assuch, the column can be moved between a lower stroke limit position,illustrated in FIGS. 1 and 2, and an upper stroke limit position, shownin FIG. 3. While in the lower stroke position, the lower end 17 a of thefirst passageway is sealingly inserted into a central aperture 20provided preferably at the center of the partition 2. The seal mayoptionally be enhanced through the use of an O-ring 25 positioned aroundthe exterior of the lower end 17 a of the first passageway. The seal,when engaged, serves to prevent blood in the cardiotomy reservoir fromentering the venous reservoir. When the seal is engaged, the upper end17 b of the first passageway is caused to be positioned at an elevationwhich is above that of the upper edges of the ducts 13 and 14.Alternatively, when the column 16 is moved into its upper strokeposition, the lower end 17 a of the first passageway 17 is extractedfrom the central aperture 20, thereby disengaging the seal and allowingblood in the cardiotomy reservoir 4 to flow directly into the venousreservoir 3. It should be noted that regardless of the position of thecolumn 16, fluid communication through the second passageway 18 issubstantially unaffected. A second O-ring 27 may optionally be providedaround the exterior of an upper portion of the column 16. The secondO-ring 27 serves to provide a seal between the upper portion of thecolumn and the portion of the housing 1 through which the column passes.

When the column 16 is at the lower stroke limit, i.e., in the positionshown in FIGS. 1 and 2, blood flowing into venous inlet connector 5enters the venous reservoir 3. If the amount of blood entering thevenous reservoir is greater than the amount exiting through the venousoutlet connector 7, the level of blood inside the venous reservoir 3 iscaused to rise. It is possible that the rising level of blood can leadto the complete filling of the venous reservoir. At this point, oneadvantage of the present invention becomes apparent, since an additionalaccumulation of blood is allowed because the blood can enter the ducts13 and 14, as well as the first passageway 17. Such excess blood canthen rise in the ducts and passageway until it overflows into thecardiotomy reservoir 4 through the ducts 13 and 14. By integrating thevenous reservoir 3 and the cardiotomy reservoir 4, the device, whenevernecessary, allows the accumulation of an amount of venous blood which isfar greater than the capacity of the venous reservoir alone.

Integration of the venous and cardiotomy reservoirs also allows air andother gaseous emboli entrained in the venous blood, resulting forexample from poor cannulation, to be released from the device by passingthrough the ducts 13, 14 and the first passageway 17 and allowing it tocollect in the upper portion of the cardiotomy reservoir 4, from whichit may exit or be withdrawn through the air outlet connector 10.

Likewise, the functionality of the cardiotomy reservoir 4 is alsoenhanced. Specifically, blood entering the cardiotomy reservoir 4through the cardiotomy inlet connector 8 gradually rises in thatreservoir until it is almost filled. Rather than completely filling thecardiotomy reservoir, however, once the blood reaches a certain level,it is caused to enter the ducts 13 and 14 and flow downwardtherethrough, accumulating in the venous reservoir 3. As such, thedevice is configured to allow excess accumulation of either venous orcardiotomy blood.

Even if excess cardiotomy blood is flowing into the venous reservoir,air and other gaseous emboli present in the venous blood can still beremoved from the device. Since the upper end 17 b of the passageway 17is configured to remain above the upper edges of the ducts 13 and 14,even if the ducts are communicating blood into the venous reservoir, thepassageway 17 remains blood-free and capable of communicating air fromthe venous reservoir into the cardiotomy reservoir, and ultimately, tothe exterior of the housing through the air outlet connector 10.

When the column 16 is positioned at its upper stroke limit, as shown inFIG. 3, all of the blood contained in the cardiotomy reservoir 4 willflow into the underlying venous reservoir 3 through the central aperture20. As such, in this configuration, the central aperture 20 acts as adrainage port which may be plugged and unplugged by the column 16.

Finally, it should be noted that a situation can arise in which theoperator does not wish to mix blood contained in the cardiotomyreservoir 4 with blood contained in the venous reservoir 3. This canoccur, for example, if undesirable substances are present in thecardiotomy blood. In that situation, the blood contained in thecardiotomy reservoir is effectively isolated from the blood in thevenous reservoir and can be completely removed from the device throughpassageway 18.

It should be noted that the advantages of the device of the presentinvention are not intended to be strictly limited to those describedabove. For example, in the embodiments of the device shown in FIGS. 1-4,the amount of blood contact with the internal surfaces of the device hasbeen minimized, as has the possibility of reverse filtration of bloodcontained within the device. Furthermore, due to the relativelynon-complex design and operation of the device, the device will respondrapidly to control manipulations by the operator.

Of course, the described invention is amenable to numerous modificationsand variations, all of which are intended to be within the scope of theinventive concept.

Thus, for example, the number of ducts provided on the partition can bedifferent from the configuration described.

Likewise, the invention is not intended to be limited to the particularmaterials employed, nor to the shapes or any dimensions employed.Rather, the device may be made according to the specific requirements ofa particular application for which its use is intended.

Equivalents

Various modifications and alterations to this invention will becomeapparent to those skilled in the art without departing from the scopeand spirit of this invention. It should be understood that thisinvention is not intended to be unduly limited by the illustrativeembodiments and examples set forth herein and that such examples andembodiments are presented by way of example only with the scope of theinvention intended to be limited only by the claims set forth herein asfollows.

What is claimed is:
 1. A combined blood reservoir comprising: a firstreservoir for receiving and containing venous blood; a second reservoirfor receiving and containing cardiotomy blood; a partition locatedbetween the first and second reservoirs, the partition having first andsecond openings defining first and second fluid paths between the firstand second reservoirs; a seal configured to be movable from a firstposition wherein the first opening is sealed to prevent flow of bloodfrom the second reservoir to the first reservoir through the firstopening and a second position wherein the first opening is not sealed toallow flow of blood through the first fluid path from the secondreservoir to the first reservoir; and an overflow member connected tothe second opening, the overflow member being configured such that whenthe seal is in the second position and the first reservoir is full bloodfrom the first reservoir overflows into the second reservoir through thesecond fluid path.
 2. The combined blood reservoir of claim 1 whereinthe overflow member is further configured such that when the seal is inthe first position and the second reservoir is full blood from thesecond reservoir overflows into the first reservoir through the secondfluid path.
 3. The combined blood reservoir of claim 2 wherein theoverflow member is a duct extending from the second opening and havingan upper outlet contained within the second reservoir.
 4. The combinedblood reservoir of claim 1 wherein the overflow member is a ductextending from the second opening and having an upper outlet containedwithin the second reservoir.
 5. The combined blood reservoir of claim 1wherein the seal comprises an axially movable column having first andsecond ends, the first end being configured to seal the first openingwhen the seal is in the first position.
 6. The combined blood reservoirof claim 5 wherein the axially movable column defines a first passagewaybetween the first and second ends, the first passageway providing afluid path between the first and second reservoirs when the seal is inthe first position.
 7. The combined blood reservoir of claim 1 whereinthe first and second reservoirs are defined by a single housing.
 8. Acombined blood reservoir comprising: a venous reservoir for containingvenous blood, the venous reservoir having a venous blood inlet and avenous blood outlet; a cardiotomy reservoir for containing cardiotomyblood, the cardiotomy reservoir being positioned above the venousreservoir and having a cardiotomy blood inlet and a gas outlet; apartition between the venous reservoir and the cardiotomy reservoir, thepartition including first and second apertures capable of providingfluid communication between the venous reservoir and the cardiotomyreservoir; a seal configured to be movable from a first position whereinthe first aperture is sealed to prevent flow of blood from thecardiotomy reservoir to the venous reservoir through the first apertureand a second position wherein the first aperture is open to allow flowof blood from the cardiotomy reservoir to the venous reservoir throughthe first opening; and at least one duct extending upward from thesecond aperture, the duct having an upper outlet contained within thecardiotomy reservoir, the duct being positioned such that when the sealis in the second position and the venous reservoir is full venous bloodfrom the venous reservoir overflows into the cardiotomy reservoirthrough the second aperture.
 9. The combined blood reservoir of claim 8wherein the duct is positioned such that when the seal is in the firstposition and the cardiotomy reservoir is full blood from the cardiotomyreservoir overflows into the venous reservoir through the secondaperture.
 10. The cardiotomy combined blood reservoir of claim 9 whereinthe seal comprises an axially movable column having first and secondends, the first end being configured to seal the first aperture when theseal is in the first position.
 11. The combined blood reservoir of claim10 wherein the axially movable column defines a first passageway betweenthe first and second ends, the first passageway providing a fluid pathbetween the venous reservoir and cardiotomy reservoir when the seal isin the first position.
 12. A combined blood reservoir comprising: avenous reservoir for receiving and containing venous blood; a cardiotomyreservoir for receiving and containing cardiotomy blood; a first fluidpassage between the venous reservoir and cardiotomy reservoir for bloodflow from the cardiotomy reservoir to the venous reservoir; a sealmovable between a first position wherein the first passage is open and asecond position wherein the first passage is closed; and a secondoverflow passage between the venous reservoir and the cardiotomyreservoir, the second passage being configured such that when the sealis in the first position and the venous reservoir is full blood from thevenous reservoir overflows into the cardiotomy reservoir through thesecond passage and when the seal is in the second position and thecardiotomy reservoir is substantially full blood from the cardiotomyreservoir overflows into the venous reservoir through the secondpassage.
 13. A combined blood reservoir comprising: a venous reservoirfor receiving and containing venous blood; a cardiotomy reservoir forreceiving and containing cardiotomy blood; a first fluid passage betweenthe venous reservoir and cardiotomy reservoir for blood flow from thecardiotomy reservoir to the venous reservoir; a seal movable between afirst position wherein the first passage is open and a second positionwherein the first passage is closed; and a second overflow passagebetween the venous reservoir and the cardiotomy reservoir, the secondpassage being configured such that when the venous reservoir is fullblood from the venous reservoir overflows into the cardiotomy reservoirthrough the second passage.